Histone deacetylase-1 represses transcription by interacting with zinc-fingers and interfering with the DNA binding activity of Sp1.

Sp1 activates the transcription of many cellular and viral genes, and histone deacetylase 1 (HDAC1) removes the acetyl group of nucleosomal core histones. Treatment of cells with the histone deacetylase 1 inhibitor, TSA, robustly activates the transcription of the Sp1-dependent promoters, suggesting the inhibition of Sp1 activity which is critical ...
in the activation of transcription, by HDAC1. We assessed the protein-protein interactions occurring between Sp1 and HDAC1, and the transcriptional regulatory mechanism controlled by this interaction. In vitro GST fusion pull down assays, co-immunoprecipitation, and mammalian two-hybrid assays revealed that the HDAC1 noncatalytic domain (a.a. 237-482) interacts directly with the zinc-finger DNA binding domain of Sp1. DNase I footprinting revealed that this interaction prevents the binding of Sp1 zinc-fingers to the target GC-box. Gal4-HDAC1 fusion, targeted proximally to the GC-boxes, potently repressed the transcription of pG5-5x(GC)-Luc, in which Sp1 potently activates transcription. This repression of transcription does not involve the deacetylase activity of HDAC1, and is accomplished by the direct protein-protein interactions which occur between the Sp1 zinc-finger DNA binding domain and HDAC1, which interferes with the promoter GC-box binding of Sp1.
Mesh Terms:
Animals, Base Sequence, Binding Sites, Cell Line, Cercopithecus aethiops, DNA, Enzyme Inhibitors, Histone Deacetylase Inhibitors, Histone Deacetylases, Hydroxamic Acids, Recombinant Proteins, Sp1 Transcription Factor, Transcription, Genetic, Two-Hybrid System Techniques, Zinc Fingers
Cell. Physiol. Biochem.
Date: Aug. 27, 2005
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